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  1. #1
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    Stationary w/HRM time to increase intensity?

    Another not so elite, lump on a stationary bike question

    Last summer (2011), I decided I'd been a lazy lump for too long after a skiing accident and sugery (leg and shoulder), I'd gained weight to 245, and wanted to get back to 210 and get my endurance / cardio back into solid territory as well.

    So, six months in, weight is proceeding as planned, down to 222-225 now, but the “fat burning” zone on the HRM no longer presents any effort, and so, is very boring even with good music. So, last week, I moved the bar, and went to a “high cardio” zone (150-155bpm; age 46), held it for an hour, and it felt good and I got the right metabolic feel from my legs.

    What I don't understand, is what does that do to my fat metabolism, as I still have another 10-15 lbs to drop, gently, by April or so. I like the feel of exercising at the higher intensity, but I don't want to mess up what's acted like a slam dunk, sure thing so far.

    Other details.
    I don't have a power meter; and don't understand them well enough to make the switch.
    I'm 5'8” but have quite a few years of noncompetitive powerlifting, thus the odd weight, and target weight.
    I cycle on the road quite a bit as well, but my impulse control is slightly worse than a squirrel's; thus, when the light goes green, the hammer goes down. This is fun, but makes anything other than a facimile of wind sprint type routines nearly impossible.

  2. #2
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    are you using an actual HRM chest strap, or going by the heart rate numbers on the stationary bike? the fact that your response to given workload in "fat burning" zone is getting easier is a good sign that your fitness is improving. but in order to a get a good read on heart rate based workouts, you really need to know your true maximum heart rate (MHR) and establish training zones based on that number - which isn't necessarily what you're getting from the stationary bike numbers if that is what you are using. in other words, I wouldn't put much stock into what you're seeing as "fat burning" and "high cardio" - those are very vague terms.

    Anyway, if you worked out for an hour at a steady pace, you're probably still working below your anaerobic threshold (AT), which is great for burning fat. and because you increased your intensity a bit, you're working closer to your AT, which is even better for burning fat. once you cross your anaerobic threshold, you're body starts looking for carbs as the primary fuel source. unlike your MHR (which is fixed), your AT is fluid - most folks in decent shape have an AT somewhere between 70-85% of their MHR. well trained athletes can see an AT between 85-95% of MHR. with training, you can raise your AT, and thus workout harder, go faster, etc.

    In a nutshell, if you can't hold a conversation and start to feel some burn in the legs, back off if you want to keep burning fat.

  3. #3
    just another gosling Carbonfiberboy's Avatar
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    When you get above the "fat-burning zone," your fat burning rate stays about the same no matter how high your HR goes, however you also burn fuel from other sources, IOW you burn more calories per unit time, so you should lose weight even faster, as long as you don't have to back the exercise time off much. One problem of going harder w/r to weight loss is avoiding eating more to replace the increased calorie burn. The other problem is recovery. If going harder reduces your total exercise time per week because you're not recovering, you may or may not lose weight faster depending on the exact times and efforts.

  4. #4
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    I use a telemetry chest strap (polar); the machine is able to pick it up. My MHR is reliably 175; there is no level of exertion that I can achieve that will push it higher, and I crash very fast once past 170. Even the let-off peak after a solid sprint won't drive it past 175.

    That said, conversation?? I'm too busy chanting Nightwish lyrics in my head.

    Thanks for the thoughts though, very helpful, I haven't intentionally trained cardio in over two decades, and I have a feeling my twenty year old body was much less vulnerable to screwups than my current 46 year old version. So I want to be careful to not mess up!

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    the weight should continue to come off by doing exactly what you're doing - not much to screw up unless you change your diet.

    in simple terms: the body needs oxygen to burn fat - aerobic means "with oxygen" and aerobic exercise happens below your AT. the body will switch to another primary fuel source when there is a lack of oxygen ("anaerobic") - anaerobic exercise happens above your AT.

    given your inclination towards higher intensities, you might consider doing some fartlek style work on the bike - just vary your intensity throughout the session, say from 70-90% of your MHR, but keep the overall volume of the workout mostly aerobic. the short bursts above AT will keep it interesting for you - but keep those efforts very short.

    it is very possible, by the way, that your true MHR is a little higher than 175 - 1 sprint or big effort isn't a reliable test for that. and if you can work out at 155bpm (about 89% of your estimated MHR) for an hour and "feel good," you need to start racing!!

  6. #6
    Senior Member locolobo13's Avatar
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  7. #7
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    there's nothing contrary to what's be said here in those links - "low intensity" and "high intensity" mean something very different to most folks who don't really train. 50% (as the usnews link suggests) isn't low intensity - that's no intensity. and 75% isn't high - "moderate," maybe.

    this is why knowing your AT is a good thing - personally, if i'm around 87% of my max, then I know i'm about to get anaerobic and switch my fuel source and that i can only maintain my current intensity for certain, limited amount of time before major system failure.

  8. #8
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    Quote Originally Posted by patrickinvt View Post
    it is very possible, by the way, that your true MHR is a little higher than 175 - 1 sprint or big effort isn't a reliable test for that. and if you can work out at 155bpm (about 89% of your estimated MHR) for an hour and "feel good," you need to start racing!!
    Considering what I feel when I've tapped 175, I think I'd be ready to do horrible, unpleasant things to whoever made me go past that point, if I managed to stay conscious that is... lol

    And I did give a range, 150-155; I can't manage to convince the machine to hold the resistance sufficient for 155, it seems to slip, like it doesn't want to believe me, or is afraid of killing me or something. (i may have to lie about my age) The average may be somewhere around 152.

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    The fat burning zone is fairly broad (see below) with the maximum fat oxidation occurring around 65% of VO2Max. I don't know what that corresponds to in HR but it's somewhere between an endurance and tempo pace. Riding at 65% of VO2Max power is a reasonably hard pace and takes some concentration to maintain for an extended ride. Riding at 75% still burns a significant amount of fat and is definitely not easy. If your riding is feeling 'too easy' you can go harder and still be in the fat burning zone.

    Pretty well any pace that you can maintain for 3-4 hrs will burn a significant amount of fat. If you're doing 2x20 intervals at threshold you'll burn more calories but they'll be mostly glycogen.


  10. #10
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    A more carefully observed and recorded evening.

    0 - 6 min warming up to 133bpm
    6 - 30 min; holding at 133bpm, at approx 102 rpm
    30 - 36min stepping up to 155bpm at 112 rpm
    36 - 90min holding at 155bpm at 112 rpm
    90 - 95min cooldown

    first 30 minutes the machine calced at 294 cal burned
    next 65 minutes calced an additional 650 cal burned.
    with 32 miles "distance"

    I'm not sure how much I really trust the cal calc, but the distance seems about right based on feel for a roady on flat terrain.

    at about the 75 min mark I did start to lose some power and coordination, had trouble taking all the load off the upstroke without losing my touch on the pedal. (no toe clips) I'm pretty sure this was leg fatigue as I wasn't needing quite as much o2 late as I was early. Might also be CNS still catching up; either way hard work and solid rest should win the day there with time.

    nb... I don't know why I like rpm's ending in twos, but I do. Odd....

  11. #11
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    Wanted to add here that this whole intersection of HR, VO2max, LTHR, HRR, calories, etc is a real mess! Even went so far as to reading stuff published in "Journal of Sports Science" (really? A Journal?!!). Whats more interesting, is that despite the complexity of the writing, the inputs to the formulas (for general population use) aren't anywhere near as complex as whats written. Age, weight, height, HR resting, HR Max, and a 2 mile run time and everything seems to flow from there. (The published VO2 max test for rabble is more a 12 minute distance test, which seems to me to be overly complicated to measure, when a close substitute for most people is so easy.) Seems a lot of complication is added trying to accommodate both Lance Armstrong and grandpa who's a sneeze away from a coronary.

    Surely I'm missing something here...

    A lot of math just to figure out how many spoons of peanut butter I need to add to zero out the wieght loss when I hit goal.
    Last edited by rwwff; 01-11-12 at 08:17 AM.

  12. #12
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    meh, it's really not that complicated. and there is no formula that can accommodate both high-level and recreational athletes - anything short of a lab test to measure one's own physiology is ball park guessing. which is fine for recreational athletes, but not as useful to those who are training based on their personal, tested physiological data. not to mention, a run test isn't necessarily going to translate to the bike - physiology can vary by mode of activity. for instance, my MHR for running is 10bpm higher than for cycling and my other stats vary too.

    anyway, if you want to geek-out a little and workout smarter, it's good to know things like MHR (to establish workout zones and get a sense of how your body is responding to a certain level of intensity) and to have a ballpark idea of AT to help guide and plan workouts/recovery. but unless one is training with goals and the intent to improve performance, the rest of the numbers don't mean much.

    you've lost 25lbs. and are doing it the right way. if you keep exercising and eating consistently, your body will eventually find an equilibrium where you don't need worry about "zeroing" out food and you won't gain or lose any significant amounts of weight.

  13. #13
    You gotta be who you be
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    A brief followup... learned a lot from these comments and some of the more "technical" material available on the web, the 155 HR is consistently tapping anaerobic metabolism, and I suspect its the combination of arthritis meds and endorphins that give me the "feels fine" evaluation. I have substantially less power outside on the road for at least 36-48 hrs after such a workout, which I'm using as an indicator that the muscles need actual recovery, which was my clue that perhaps my "feel" of the session might not be reflecting reality. (not the first time there...)

    Anyway, thanks for the insight.

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